Which of the following is the hallmark of programmed cell death?

Apoptosis results from the activation of enzymes called caspases (so named because they are cysteine proteases that cleave proteins after aspaic residues). The activation of caspases depends on a finely tuned balance between production of pro- and anti-apoptotic proteins. Two distinct pathways converge on caspase activation: the mitochondrial pathway and the death receptor pathway.( Robbins Basic Pathology, 9th edition, page 19 )